KANSAS CITY, Mo. -- The Kansas City Chiefs over the past month have signed as free agents or traded for five players who could be starters or key rotational pieces on defense. Yet the Chiefs still have holes to fill in their defensive lineup before they start offseason practice in May.

That speaks to the size of the Chiefs' defensive renovation. An inept defense prevented the Chiefs last season from advancing to the Super Bowl for the first time in 49 years. So, the Chiefs to an extent are starting over on D. They have a new defensive staff led by coordinator Steve Spagnuolo and a new 4-3 base system.

Mathieu, who was given a three-year contract worth $42 million, is the player the Chiefs felt they had to have in order to make these changes work. He will be asked to do many of the things Berry did for the Chiefs, including being a leader in their locker room.

“There were a lot of safeties out there, but I don’t think there are many safeties out there that can really do everything on the field: call the show; run everything back there; play down in the box; play slot; blitz off the edge; play center field," Kansas City general manager Brett Veach said. “So, when you get a guy like that and guys like that aren’t cheap.

“When we started this free-agency process with coach Spagnuolo, I remember him coming down to the office after we gave him a list of safeties to watch. He would go down the list and he would say strengths and weaknesses and, ‘I like this guy,’ this and that, ‘Here’s what he can do, here’s what he can’t do.’ He got to [Mathieu] and he said, ‘I’m struggling to find what he can’t do.’

“I said, ‘Say no more, we’re going to get him.’"

The Chiefs believe Mathieu is a transcendent player, one who they believe makes everyone around him a better defender.

“I think that’s also part of the reason why I’m here, as well," Mathieu said. "I think we all know what the offense can do. I think it’ll be my job to come in here, try to get some direction, try to give guys some motivation, some inspiration, and then be an every-day factor. I want to be the same guy I am in the weight room that I am on the football field. That’s what I’m really looking forward to bringing to this team and ... I’m going to try my best to do that every single day.”

Others will be in the mix for playing time soon. The Chiefs are still looking to the NFL draft for more help. They have an additional pick in the second round because of last year’s trade that sent cornerback Marcus Peters to the Los Angeles Rams.

“When you win games, you’ve got to pick at the end of every round," Veach said of the Chiefs, who select 29th in the draft's first round. “So to do things, you need [extra] picks."